This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We reported previously that the rhesus embryonic stem cell line 366.4 could be induced to differentiate into cultures that were largely serotonin neurons. We proposed to harvest serotonergic neurospheres derived from 366.4 rhesus embryonic stem cells, which were transfected with green fluorescent protein (GFP). Then, the neurospheres were to be implanted bilaterally into the hypothalamus. After periods of 1-4 months, the brain was to be removed for neuroanatomical examination and laser capture of implanted neurons.